The invention generally concerns a device for displaying a marking, in particular a line or a distance, on a playing field of a sports facility.
Generally, there has always been the necessity in most sports to regiment the game in order to be able to play it fairer. A substantial feature is to edge the playing field. For that reason lines are drawn or other markings are correspondingly applied on the surface of the playing field before the game.
A variant to provide the same surface easily with boundaries for different sports is disclosed in the EP 0 423 218 B1. This is effected in that marking lines are projected onto the playing surface via a laser. Thus, these projected lines temporarily define the playing field markings on an otherwise unmarked surface and it can be fast switched between different sports.
In addition, more and more technical aids are used in many sports in order to organize the game fairer, more attractive, clearer, faster and more thrilling. Also more analyzing possibilities are used for spectators, coaches and players after the game. Also aids for referees are more often used.
An example of such a monitoring device on a playing field is disclosed in DE 10 2006 020 018 A1. This is especially about promptly informing referees during their decision making regarding the rule observance on the basis of objective factual findings which, however, does not challenge their decisions. For that reason, playing field points are calculated, an operating unit is provided, a camera unit together with a control and evaluation unit is used, and a display unit for replaying the events of the game is used, so that each game situation is reproducible, evaluable and displayable via a display unit and can be supplied for an analysis.
A similar system is described in DE 10 2007 049 147 A1 which is about the use of a sensor system for detecting movement sequences of persons, sport equipment, and game situations in sports. For that reason, sensor devices in the form of PMD sensors are provided. A camera can be associated with each sensor device. The sensor system is thus formed in such a way that corresponding distance information detected by the associated sensor device is associated with objects, which are displayed with the aid of the camera. For example, an evaluation unit determines by predefined algorithms whether a rule violation has happened, thus whether the ball has passed the touchline or one of the bylines at goal or whether a player was offside in the moment of the pass. Furthermore, an evaluation can be effected in such a way that it is determined whether the ball has passed the goal line or not.
A latter variant with a display of whether a goal was scored or not was successfully utilized for the first time on a large scale during the Football World Cup 2014 under the name of “Goal Control”.
However, in order to not only enable a verification or a monitoring in hindsight, but to utilize technical aids already during the game, several aiding systems are known from some other sports.
For example, the U.S. Pat. No. 4,090,708 shows a possibility in order to project the most relevant distance lines (first down line and line of scrimmage) during an American football game via laser onto the field. For that reason lasers move on guide rails attached alongside the playing field, wherein during the game the corresponding lines are displayed across the playing field by the lasers.
With the Football World Cup 2014, a further technical aid for the use during a football game has been established, namely the so-called “free kick spray”. With the aid of this spray, the referee can mark the position of the ball visibly for each player during the game when there is a free kick and can also spray the necessary free kick distance of 9.15 m to the ball onto the playing field, so that the opposing team forms the wall in the correct distance to the ball. Thereby, the fairness is improved and also the observing of the necessary distance is mostly effected faster than with the sheer forcing back by the referee. An example for the exact composition and use of such a spray is disclosed in the DE 601 06 410 T2.
This system introduced only recently has indeed proved beneficial already, but still has disadvantages. For example, the sprayed distance is still based on the estimation of the referee and thus can significantly differ from the rule-consistent 9.15 m. Moreover, this distance is valid in a circle around the football; however, the distance is mostly only sprayed in an area facing in the direction of the football goal. So it can happen that a player which is beside the wall and beside the sprayed line is considerably nearer to the football than allowed. Thus, for example, in the case of a short passed free kick, this player is illegally too fast at the ball and at the opponent.
The invention thus concerns a device for displaying a marking in the form of a distance to be kept between a game equipment, in particular a football, and a participant on a playing field of a sports facility. Such a display device includes a display device for projecting light beams representing the marking onto the playing field, wherein the projected light beams display the distance to be kept and can be projected at least in sections in the shape of a circle, in particular at a distance of 9.15 m, around the game equipment on the playing field. Further, the invention concerns a method for projecting such a marking on a playing field.
With such a display device, the exact distance of a player to the ball can therefore be displayed around the ball, whereby the disadvantages of the “free kick spray” are remedied. Such a device for generating a marking on a playing field is disclosed in DE 101 24 012 A1. There, a laser or light source is provided, wherein, by the corresponding light beams, the markings are generated on the playing field. This device can be operated by a remote control. A circle line with a predefined radius is generated by a light beam on the playing field around a point on the playing field. This device is mounted above the playing field, in particular on a roof of the stand and/or on a mast like a flood light mast. By this stationary device, the laser beams are bundled via a lens system and are directed onto the playing field. Also several such devices can be provided.
A quite similar system is disclosed in the US 2005/0162257 A1. A laser light beam is projected on the playing field also from a stadium roof or from masts in order to display the necessary free kick distance. This system can be activated via the whistle of the referee. It is noted that a “spot light” mechanism automatically focuses on the position of the ball. The detailed configuration, though, is not mentioned.
Disadvantageously in both systems, it cannot be guaranteed that the desired marking is entirely displayed because participants can be in the way. Especially if the light source is attached to a mast or to the stadium roof behind the wall, the marking cannot be displayed in front of the wall. This problem could be prevented in that several light sources from different angles are directed on the playing field which, however, would lead to considerable extra costs and to a multiplication of the necessary components. Moreover, there is still the disadvantage that the distance to the playing field is very large depending on the stadium height and breadth, wherefore powerful and thus cost-intensive lasers must be used in order to reach a sufficiently visible display of the marking. Additionally, the position of the ball often cannot be determined for certain, especially when the ball is hidden for the remote control arranged relatively far away from the “spot light” mechanism. Thus, it cannot always be guaranteed that the system even “knows” or can detect where the ball is just situated.